[travis] ensure to exit with error on toranj build failure (#3197)
[travis] ensure to exit with error on toranj build failure (#3197)


turon/openthread,LeZhang2016/openthread,chshu/openthread,gandreello/openthread,lanyuwen/openthread,openthread/openthread,abtink/openthread,turon/openthread,erja-gp/openthread,librasungirl/openthread,gandreello/openthread,jwhui/openthread,lanyuwen/openthread,bukepo/openthread,lanyuwen/openthread,lanyuwen/openthread,openthread/openthread,bukepo/openthread,erja-gp/openthread,openthread/openthread,gandreello/openthread,srickardti/openthread,jwhui/openthread,bukepo/openthread,LeZhang2016/openthread,srickardti/openthread,erja-gp/openthread,srickardti/openthread,LeZhang2016/openthread,abtink/openthread,jwhui/openthread,librasungirl/openthread,chshu/openthread,turon/openthread,jwhui/openthread,LeZhang2016/openthread,bukepo/openthread,erja-gp/openthread,LeZhang2016/openthread,erja-gp/openthread,openthread/openthread,lanyuwen/openthread,LeZhang2016/openthread,gandreello/openthread,gandreello/openthread,chshu/openthread,chshu/openthread,lanyuwen/openthread,erja-gp/openthread,abtink/openthread,abtink/openthread,turon/openthread,srickardti/openthread,librasungirl/openthread,gandreello/openthread,chshu/openthread,librasungirl/openthread,chshu/openthread